JPH02177995A - Button holding mechanism for button sewing machine - Google Patents

Abstract

PURPOSE:To prevent the protrusion of a button, the dislocation of a button holding position, the breaking of a needle, and the damage of the button by elevating a button holding member only at the completion of one sewing cycle in two thread cutting operations to be executed in one sewing cycle. CONSTITUTION:An elevating/lowering member 5 respectively lowers and cuts a thread with a thread cutting mechanism A at points where the former 1/2 sewing cycle and the latter 1/2 sewing cycle are competed. In a thread cutting operation in the former 1/2 cycle, since a pressing member 13 provided on the elevating/lowering 5 is made to retreat from the upper part of a button holding member 3 with moving members 14, 16, and 17, the pressing member 13 never depresses the button holding member 3 when the elevating/lowering member 5 is lowered, and the button holding member 3 is never elevated. In another thread cutting operation in the latter 1/2 cycle, since the moving members 14, 16, and 17 allow the pressing member 13 to be positioned at the upper part of the button holding member 3, one edge part of the button holding member 3 is depressed accompanying the lowering of the elevating/lowing member 5, and the button holding member 3 is elevated. The button is surely held at a sewing and fixing position in a button sewing operation, and the occurrence of the protrusion of the button from the button holding member 3, the dislocation of the button, etc., can be prevented.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a button holding mechanism for a button sewing machine, and in particular, to a button holding mechanism for a button sewing machine, and in particular to a button holding mechanism for a button sewing machine, and in particular to a mechanism for preventing upper thread from forming between two pairs of button holes of a four-hole button. This invention relates to a button holding mechanism for a button sewing machine.

[Conventional technology]

In a button sewing machine, two pairs of buttonholes of a four-hole button are sewn in one sewing cycle.

When thread trimming is performed every 1/2 cycle, that is, when thread trimming is performed every time a pair of buttonholes are sewn, and when the thread is trimmed only at the end of the second half cycle, that is, when the second pair of buttonholes are sewn. There are two cases in which the thread trimming operation is performed only at the end of the process.

Among these, in the latter case, different pairs of buttonholes Ba□ of button B are shown in FIG. 3(a).

A so-called crossing thread (■) is formed between the thread I and Bbl, but in the former case, a crossing thread (■) is not formed (see FIG. 3(b)). The presence of the crossover thread (2) may impair the appearance of the sewn product, so high-end products are usually sewn without the latter.

[Problem to be solved by the invention]

However, in the button holding mechanism of a conventional button sewing machine, the button holding member that clamps the outer periphery of the button and presses the fabric against the presser foot lower plate works in conjunction with its operating mechanism during thread trimming. Since the button was moved upward from the throat plate, when sewing without a crossover thread as described above, the button holding member rises in conjunction with the thread trimming operation after the first half of the 172 sewing cycles. fi which is lowered at the beginning of the next second half 172 sewing cycle.
12, problems such as the button popping out from the button holding member, the holding position of the button shifting, and the suture needle interfering with the button during the second half of the 172-cycle sewing operation may cause needle breakage or button damage. there were.

For this reason, a drive source separate from the thread trimming mechanism, such as an air cylinder or an electromagnetic solenoid, is used, and this is electrically controlled by a control device to prevent the button press member from rising at the end of the 1/2 sewing cycle. Some proposals have also been made to do so. However, in this case, it is necessary to add a new drive source and control device, resulting in a problem of a significant increase in cost.

The present invention has been made in view of the above-mentioned problems, and is a button holding mechanism that uses an inexpensive mechanical configuration using a sewing machine's drive source to raise the button holding member only at the end of one sewing cycle. For the purpose of providing.

[Means to solve the problem]

The present invention provides a button sewing machine which performs a sewing operation on two pairs of buttonholes of a four-hole button during one sewing cycle, and performs a thread cutting operation every 1/2 sewing cycle. A pressing member is rotatably attached to the elevating member that performs the thread cutting operation, and is moved from a first position to a second position by sliding contact with an operating cam that rotates once every sewing cycle. A moving member is provided for moving the pressing member from above the button holding member to a predetermined retracted position, and the moving member is moved to a second position just before the actuating cam is lowered by the elevating member in the first half sewing cycle. , the movable member is retracted to the first position in the latter half of the 172nd sewing cycle.

[Function] In this invention, the elevating member descends at the end of the first half and the second half of 172 sewing cycles, and the thread is cut by the thread cutting mechanism. At this time, during the thread cutting operation in the first half cycle, the pressing member provided on the lifting member is retracted from above the button holding member by the moving member, so the pressing member presses the button holding member when the lifting member is lowered. The button holding member does not rise. In addition, during the thread cutting operation in the second half cycle, the moving member positions the pressing member on the button holding member, so as the elevating member descends, one end of the button holding member is pushed down and the button holding member is raised. .

As a result, the button is reliably held in the stomach in position A during the sewing operation, and the button is prevented from popping out from the button holding member or being misaligned.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIGS. 1 and 2.

In the figure, 1a is a sewing machine arm that has a suture needle (not shown), 1b is a sewing machine bed that has a presser foot lower plate 2, etc., and 3 is a feed table that slides on the sewing machine bed.It is rotatably supported on four fulcrum shafts. This is a button holding member. This button holding member 3 is provided with a pair of button holding feet 3a and 3b facing the presser foot lower plate 2 at one end (the right end in the figure) for holding the outer periphery of the button. End 3c
By pressing and releasing , the presser foot lower plate 2 is moved up and down. 5 is an elevating plate that is movable in the vertical direction.

Its upper end is rotatably supported by the sewing machine arm 1a via a link member 6, and its lower end is rotatably supported by the sewing machine bed 1b.
It is rotatably connected to one end of a link member 8 provided therein, and is normally biased upward.

Further, the link member 8 is connected to an arm 9 that rotates a predetermined amount around a shaft 8a immediately before the end of each 172 sewing cycles, and as the arm 9 rotates, the link member 8 moves the lifting plate 5. It is designed to move to the right in the diagram.

Reference numeral 1o designates an eccentric cam that rotates once per needle in synchronization with the vertical movement of the suture needle.The rotation of this eccentric cam 10 causes the two-pronged rod 11 to rotate and swing around the shaft 12, and its engaging portion 11a moves vertically. It is designed to swing in the direction. Further, the engaging portion 11a of the two-pronged rod 11 is adapted to engage with a U-shaped groove 5a formed in the elevating plate 5 when the elevating plate 5 moves from side to side.

Reference numeral 13 denotes a pressing member whose middle part is pivoted above the elevating plate 5, and its lower end 13a is at the initial position @ (raised position) of the elevating plate 5.
It is located above the other end 3c of the button holding member 3 in the state shown in FIG. Reference numeral 14 denotes a movable plate that moves in the left-right direction on the sewing machine bed 1b, and is always urged rightward by a tension spring 15. Reference numeral 16 denotes an actuating plate erected and fixed on the movable plate 14, and an engaging groove 16 at its upper end engages with an engaging pin 13b provided at the upper end of the pressing member 13.
a is formed.

Reference numeral 17 denotes a V-shaped operating arm rotatably attached to the shaft 9a, one end of which is engaged with the movable plate 14, and a rotating roller 17a attached to the other end. has been done. Note that the above 14 and 16 degrees 17 constitute a moving member.

Reference numeral 18 denotes an operating cam which rotates once per sewing cycle of the four-hole button B (see FIG. 3), and the rotary roller 17a is constantly in pressure contact with the outer peripheral surface of the operating cam.

Note that one sewing cycle in this embodiment has 16 stitches, and in the first half 1/2 cycle (8 stitches), one pair of buttonholes BaztBa2 is sewn, and in the second half 172 sewing cycles, the other pair of buttonholes Bb1. It is designed to wear Bb2. Further, a cam groove 18a is formed on the outer circumferential surface of the operating cam 18.

This cam groove 18a is approximately 1
It is formed so as to be in contact with the rotary roller 17a for a period from the needle to about one stitch immediately after the second half of the 172 sewing cycle, that is, for about two stitches. Further, 19 is a thread trimming knife located on the lower surface of the throat plate 7, which is horizontally moved by links 20, 2122, 23.24 linked to the elevating plate 5 just before the end of each 1/28ff cycle in the first half and the second half. It is designed to cut the thread. Note that these 19 to 24 constitute a thread cutting mechanism A.

Based on the above configuration, the operation will be explained next.

At the start of sewing, the button holding member 3 holding the four-hole button B descends to press and fix the fabric on the lower presser foot 2. Moreover, at this time, since the elevating plate 5 is pressed to the right in the figure by the arm body 9 and the link member 8, the U-shaped groove 5a and the engaging portion 11A of the two-pronged rod 11 are not engaged with each other. state, and the elevating plate 5 is in the initial position, that is, in the raised position.

Therefore, at the same time as sewing starts, the eccentric cam 10 rotates and the two-pronged rod 11 swings, but the movement is not transmitted to the elevating plate 5. Note that FIG. 1 shows the state immediately before the start of the sewing operation.

After this, when the sewing operation for the pair of buttonholes Ba and Ba2 reaches approximately 7 stitches, the rotating roller 17 of the operating arm 17
a falls into the cam groove 18 from the circumferential surface of the operating cam 18,
The actuating arm 17 rotates in the direction of arrow a. As a result, the movable plate 14 and the actuating plate 16 rotate to the right (in the direction of arrow e) according to the tension spring 15. As a result, the lower end 13a of the press plate 13 rotates in the direction of the hour hand (in the direction of arrow C). As a result, the lower end 13a of the pressing plate 13 moves to a second position, that is, a position retracted from above the other end 3c of the button holding plate 3.

And just before the end of the first half of the M cycle (
(approximately 7.5 stitches), the arm body 9 and the link member 8 are operated by a cam mechanism (not shown), and the elevating plate 5 is moved to the left to engage the U-shaped groove 5a and the engaging portion 11a of the two-pronged rod 11. engage with. As a result, the elevating plate 5 is pushed down by the lowering operation of the engaging portion 11a.

At the same time, the links 20, 21, 22, 23, and 24 operate, and the thread cutting knife 19 moves horizontally to cut the thread. Since the pressing member 13 is retracted from above the button holding member 3 as described above, the lower end portion L3a does not come into contact with the button holding member 3 even if it descends together with the elevating plate 5. Therefore, even if the thread cutting operation is performed as described above, the lowered state of the button holding member 3 is maintained.

Thereafter, at the same time as the second half of the sewing cycle starts, the arm body 9 and the link member 8 are activated to move the lifting plate 5 to the right.
The engagement between the U-shaped groove 5a and the engaging member 11a is released, and the elevating plate 5 is returned to the initial position (upper). Note that during the return operation of the elevating plate 5, the rotating roller 17a is still in contact with the cam groove 18a, so the pressing member 13 is held at the second position, and when rising together with the elevating plate 5, the button holding member There is no interference with 3. Further, the rotating roller 17a is then rotated for about 1/2 sewing cycle in the latter half.
When the needle is moved, the operating cam rides on the circumference of the operating cam 8 and rotates counterclockwise (in the direction indicated by the arrow), moving the movable plate 14 and the operating plate 16 in the direction indicated by the arrow f, and presses the pressing member 13. 3 in a counterclockwise direction to position the lower end 3a in the first position, that is, in the upper position of the other end of the button holding member 3. Then, as the sewing operation progresses, just before the second half of the sewing cycle is completed (approximately 15.5 stitches), the arm body 9 and the link member 8 operate again to connect the U-shaped groove 5a and the engaging portion 11.
a, and the elevating plate 5 is lowered together with the engaging portion 11a to perform the thread cutting operation. Also, at this time, since the rotating roller 17a rides on the circumference of the operating cam]8, the pressing member 13 is in the first position, and as the elevating plate 5 descends, the other end of the button holding portion 3 press down. As a result, the button holding legs 3a and 3b of the button holding member 3 rise, the pressing of the cloth is released, and one sewing cycle is completed.

(Effects of the Invention) As explained above, the button holding mechanism of the button sewing machine according to the present invention has an inexpensive mechanical configuration using the sewing machine's drive source, and is capable of cutting threads twice during one sewing cycle. Since the button holding member can be raised only at the end of one sewing cycle, the button does not pop out from the button holding member or the button holding position shifts during the sewing operation, which prevents problems such as needle breakage and button damage. There is no risk of any inconvenience occurring.

These are plan views showing the sewn state, where (a) shows a state with a crossover thread, and (b) shows a state without a crossover thread.

3... Button holding member 5 - Lifting member 13... Pressing member 16... Operating plate 14... Moving plate Moving member 17... Operating arm 18... Operating cam A... Thread trimming mechanism B ...Button B al, B a2. B bl, B b2-Buttonhole

[Brief explanation of the drawing]

Claims (1)

[Claims] By releasing the pressure on one end, the button holding member that moves up and down is lowered to hold the four-hole button on the cloth, and in the first half cycle, the button is sewn into the pair of buttonholes. do the
In the latter 1/2 cycle, the same button is sewn into the other pair of buttonholes, and just before the end of the sewing operation in each 1/2 cycle, the elevating member is lowered from the initial position and the thread trimming mechanism is activated. In the button sewing machine, the pressing member rotatably attached to the elevating member slides into contact with an operating cam that rotates once during one sewing cycle in synchronization with the drive shaft. movement from a first position to a second position, positioning the pressing member on the button holding member at the first position, and retracting the pressing member from above the button holding member at the second position. the actuating cam moves the movable member to the second position immediately before lowering the elevating member in the first half sewing cycle, and moves the movable member to the first position in the second half sewing cycle.
A button holding mechanism for a button sewing machine, characterized in that the button is moved to a position.